Visionary author Arthur C Clarke, who died in Sri Lanka last night, gave science-fiction credibility by postulating theories based on accepted scientific theory.

He was credited with the concept of communications satellites in 1945, decades before they became a reality. Geosynchronous orbits, which keep satellites in a fixed position relative to the ground, are called Clarke orbits.

Clarke had battled debilitating post-polio syndrome since the 1960s and sometimes used a wheelchair.

After a failed marriage he moved to Sri Lanka, then Ceylon, in 1956, lured by his interest in marine diving which he said was as close as he could get to the weightless feeling of space.

"I'm perfectly operational underwater," he once said.

He authored 2001: A Space Odyssey, which became a cult classic film made by director Stanley Kubrick, but he was regarded as far more than a science-fiction writer winning worldwide acclaim with more than 100 books on space, science and the future.

Sir Arthur, who was born in Minehead, Somerset, and was a radar specialist for the RAF in the Second World War, began writing in the 1940s.

His status as the grand old man of science-fiction was threatened when, in 1998, allegations of child abuse, which he strenuously denied and was cleared of, caused the confirmation of a knighthood to be delayed.